U.S. patent application number 15/816783 was filed with the patent office on 2018-05-03 for composition for coating photoresist pattern and method for forming fine pattern using the same.
This patent application is currently assigned to SK hynix Inc.. The applicant listed for this patent is SK hynix Inc.. Invention is credited to Jeong Hoon An, Keun Kyu Kong, Sung Jae LEE, Yun Seop Oh, Jae Hee Sim.
Application Number | 20180120707 15/816783 |
Document ID | / |
Family ID | 58500081 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180120707 |
Kind Code |
A1 |
LEE; Sung Jae ; et
al. |
May 3, 2018 |
COMPOSITION FOR COATING PHOTORESIST PATTERN AND METHOD FOR FORMING
FINE PATTERN USING THE SAME
Abstract
Disclosed are a composition for coating a photoresist pattern
and a method for forming a fine pattern using the same. The
composition for coating a photoresist pattern includes a polymer
compound containing a hydroxyl group and an ammonium base, and a
solvent. The method for forming a fine pattern includes coating the
composition on a previously formed photoresist pattern to thereby
effectively reduce the size of a photoresist contact hole or space,
and can be used in all semiconductor processes in which a fine
pattern is required to be formed.
Inventors: |
LEE; Sung Jae; (Gyeonggi-do,
KR) ; Kong; Keun Kyu; (Seoul, KR) ; Sim; Jae
Hee; (Chungcheongbuk-do, KR) ; An; Jeong Hoon;
(Gyeonggi-do, KR) ; Oh; Yun Seop; (Gyeonggi-do,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SK hynix Inc. |
Gyeonggi-do |
|
KR |
|
|
Assignee: |
SK hynix Inc.
|
Family ID: |
58500081 |
Appl. No.: |
15/816783 |
Filed: |
November 17, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15058816 |
Mar 2, 2016 |
|
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15816783 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/405 20130101;
G03F 7/0035 20130101; G03F 7/32 20130101; H01L 21/0273 20130101;
G03F 7/16 20130101; H01L 21/0274 20130101; G03F 7/40 20130101; H01L
21/324 20130101; G03F 7/0397 20130101 |
International
Class: |
G03F 7/40 20060101
G03F007/40; H01L 21/324 20060101 H01L021/324; H01L 21/027 20060101
H01L021/027; G03F 7/00 20060101 G03F007/00; G03F 7/32 20060101
G03F007/32; G03F 7/16 20060101 G03F007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2015 |
KR |
10-2015-0142360 |
Claims
1. A method for forming a fine pattern, comprising: a) forming a
first photoresist pattern over an underlying layer; b) coating the
composition for coating a photoresist pattern on the first
photoresist pattern to form a composition layer; c) baking the
photoresist pattern coated with the composition layer to form a
coating layer at an interface between the photoresist pattern and
the composition; and d) removing an unreacted portion of the
composition layer to form a second photoresist pattern; wherein the
composition for coating a photoresist pattern comprises a polymer
compound and a solvent, wherein the polymer compound is represented
by the following formula 1: ##STR00014## wherein R* and R** are
each a hydrogen or a methyl group, wherein R.sub.1 is a linear or
branched hydrocarbon group having 1 to 18 carbon atoms, an ether
group containing a linear or branched hydrocarbon group having 1 to
18 carbon atoms, or a cyclic hydrocarbon group having 3 to 18
carbon atoms, wherein R.sub.2 to R.sub.4 are each independently a
linear or branched hydrocarbon group having 1 to 18 carbon atoms,
or a cyclic hydrocarbon group having 3 to 18 carbon atoms, wherein
N.sup.+X.sup.- is an ammonium salt, and wherein the molar ratio of
a:b ranges from 10:90 to 90:10.
2. The method of claim 1, wherein the baking is performed at a
temperature ranging from 100.degree. C. to 200.degree. C.
3. The method of claim 1, wherein the removing of the unreacted is
portion of the composition layer is performed using water or an
alkaline developer.
4. The method of claim 1, wherein the first photoresist pattern has
a first width, and wherein the first width is 30-300 nm.
5. The method of claim 1, wherein the second photoresist pattern
has a second width, and wherein the second width is 10-40% greater
than the first width.
6. The method of claim 1, wherein the coating layer has a thickness
of 300-3000 .ANG..
7. The method of claim 10, wherein the coating layer has a third
width, and wherein the third width is 5-20% of the first width.
8. The method of claim 1, wherein N.sup.+X.sup.- is
NH.sup.+Cl.sup.-, NH.sup.+I.sup.-, NH.sup.+HSO.sub.4.sup.-,
(NH.sup.+)COO.sup.-, (NH.sup.+)SO.sub.3.sup.-,
(NH.sup.+)SO.sub.4.sup.-, (NH.sup.+)PO.sub.3.sup.-, or
(NH.sup.+)PO.sub.4.sup.-.
9. The method of claim 1, wherein the polymer compound includes a
compound represented by the following formulas 1a to 1h or a
combination thereof: ##STR00015## ##STR00016##
10. The method of claim 1, wherein the polymer compound is
represented by the following formula 1, and is contained in an
amount of 0.1 wt % to 3 wt % based on the total weight of the
composition.
11. The method of claim 1, wherein the solvent includes
alcohol.
12. The method of claim 11, wherein the alcohol is selected from
the group consisting of C.sub.1-C.sub.10 alkylalcohol,
C.sub.2-C.sub.10 alkoxy alkylalcohol, and a combination
thereof.
13. The method of claim 12, wherein the C.sub.1-C.sub.10
alkylalcohol is selected from the group consisting of methanol,
ethanol, propanol, isopropanol, n-butanol, sec-butanol, t-butanol,
1-pentanol, 2-pentanol, 3-pentanol, 2,2-dimethyl-1-propanol, and a
combination thereof.
14. The method of claim 12, wherein the C.sub.2-C.sub.10 alkoxy
alkylalcohol is selected from the group consisting of
2-methoxyethanol, 2-(2-methoxyethoxy)ethanol, 1-methoxy-2-propanol,
3-methoxy-1,2-propanoldiol, and a combination thereof.
15. The method of claim 1, wherein the composition further includes
a surfactant.
16. The method of claim 15, wherein the surfactant is contained in
an amount of 0.001 wt % to 0.1 wt % based on the total weight of
the composition.
Description
CROSS-REFERENCES TO RELATED APPLICATION
[0001] This application is a division of U.S. patent application
Ser. No. 15/058,816 filed on Mar. 2, 2016, which claims priority
under 35 U.S.C. .sctn. 119(a) to Korean application number
10-2015-0142360, filed on Oct. 12, 2015. The disclosure of each of
the foregoing applications is incorporated herein by reference in
its entirety.
BACKGROUND
1. Technical Field
[0002] Various embodiments generally relate to a composition for
coating a photoresist pattern and a method for forming a fine
pattern using the same, and more particularly, to a composition for
coating a photoresist pattern, which includes a polymer compound
and a solvent. The polymer compound contains a hydroxyl group and
an ammonium base. The method for forming a fine pattern includes
coating the composition on a previously formed photoresist pattern
to effectively reduce the size of a photoresist contact hole or
space. The composition can be used in all semiconductor processes
in which a fine pattern is required to be formed.
2. Related Art
[0003] In recent years, as technology for fabricating semiconductor
devices has been developed and the fields of application of memory
devices have been expanded, the development of lithography
processes that is, the development of photoresist materials, new
light sources, and light exposure systems, has been accelerated in
order to develop memory devices having increased integration
density. However, since a resolution obtainable by use of KrF and
ArF exposure systems which are currently commonly used is limited
to about 0.1 .mu.m, it is difficult to form a pattern smaller than
this limit in order to fabricate a highly integrated semiconductor
device.
[0004] Accordingly, various embodiments according to the present
invention are novel and capable of overcoming the resolution limit
of conventional photoresist patterns and forming a fine pattern
without using expensive materials and complex process steps.
SUMMARY
[0005] Various embodiments are directed to a composition for
coating a photoresist pattern hereinafter also referred to as the
"photoresist pattern coating composition", which includes: a
polymer compound containing as end groups a hydroxyl group and an
ammonium base, which are capable of cross-linking with a
photoresist material to form a coating layer on the surface of the
photoresist material; and a solvent.
[0006] Other embodiments are directed to a method for forming a
fine pattern, which includes coating the photoresist pattern
coating composition on a previously formed photoresist pattern to
thereby effectively reduce the size of a photoresist contact hole
or space, and which is applicable to all devices in which a fine
pattern is required to be formed.
[0007] In an embodiment, A composition for coating a photoresist
pattern, comprising: a polymer compound and a solvent, wherein the
polymer compound is represented by the following formula 1:
##STR00001##
[0008] wherein R* and R** are each a hydrogen or a methyl group,
wherein R.sub.1 is a linear or branched hydrocarbon group having 1
to 18 carbon atoms, an ether group containing a linear or branched
hydrocarbon group having 1 to 18 carbon atoms, or a cyclic
hydrocarbon group having 3 to 18 carbon atoms, wherein R.sub.2 to
R.sub.4 are each independently a linear or branched hydrocarbon
group having 1 to 18 carbon atoms, or a cyclic hydrocarbon group
having 3 to 18 carbon atoms, wherein is a group capable of forming
an ammonium salt, and wherein the molar ratio of a:b ranges from
10:90 to 90:10.
[0009] The N.sup.+X.sup.- is NH.sup.+Cl.sup.-, NH.sup.+I.sup.-,
NH.sup.+HSO.sub.4.sup.-, (NH.sup.+)COO.sup.-,
(NH.sup.+)SO.sub.3.sup.-, (NH.sup.+)SO.sub.4.sup.-,
(NH.sup.+)PO.sub.3.sup.-, or (NH.sup.+)PO.sub.4.sup.-.
[0010] The polymer compound includes a compound represented by the
following formulas 1a to 1h or a combination thereof:
##STR00002## ##STR00003##
[0011] The polymer compound represented by formula 1 is contained
in an amount of 0.1-3 wt % based on the total weight of the
composition.
[0012] The solvent includes alcohol, and wherein the composition
further includes a surfactant.
[0013] The alcohol is selected from the group consisting of
C.sub.1-C.sub.10 alkylalcohol, C.sub.2-C.sub.10 alkoxy
alkylalcohol, or a combination thereof.
[0014] The C.sub.1-C.sub.10 alkylalcohol is selected from the group
consisting of methanol, ethanol, propanol, isopropanol, n-butanol,
sec-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol,
2,2-dimethyl-1-propanol, and a combination thereof.
[0015] The C.sub.2-C.sub.10 alkoxy alkylalcohol is selected from
the group consisting of 2-methoxyethanol,
2-(2-methoxyethoxy)ethanol, 1-methoxy-2-propanol,
3-methoxy-1,2-propanoldiol, and a combination thereof.
[0016] The surfactant is contained in an amount of 0.001-0.1 wt %
based on the total weight of the composition.
[0017] A method for forming a fine pattern, comprising: [0018] a)
forming a first photoresist pattern over an underlying layer;
[0019] b) coating the composition of claim 1 on the first
photoresist pattern to form a composition layer; [0020] c) baking
the photoresist pattern coated with the composition layer to form a
coating layer at an interface between the photoresist pattern and
the composition; and [0021] d) removing an unreacted portion of the
composition layer to form a second photoresist pattern.
[0022] The baking is performed at a temperature ranging from
100.degree. C. to 200.degree. C.
[0023] The removing of the unreacted portion of the composition
layer is performed using water or an alkaline developer.
[0024] The first photoresist pattern has a first width, and wherein
the first width is 30-300 nm.
[0025] The second photoresist pattern has a second width, and
wherein the second width is 10-40% greater than the first
width.
[0026] The coating layer has a thickness of 300-3000 .ANG..
[0027] The coating layer has a third width, and wherein the third
width is 5-20% of the first width.
[0028] A semiconductor device comprising: a photoresist pattern
formed over a substrate; and a coating layer formed over the
photoresist pattern, wherein the photoresist pattern includes a
photoresist material, and wherein the coating layer includes a
cross-linking material between the photoresist material and the
composition represented by the following formula 1.
##STR00004##
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1 to 3 are schematic process views illustrating a
method for forming a fine pattern using a composition of an
embodiment.
[0030] FIG. 4 is a photograph of a first contact hole pattern
obtained before application of a coating composition according to
an embodiment.
[0031] FIG. 5 is a photograph of a second contact hole pattern
obtained after application of a coating composition according to an
embodiment.
DETAILED DESCRIPTION
[0032] Hereinafter, a composition for coating a photoresist pattern
and a method for forming a photoresist pattern using the same will
be described with reference to the accompanying drawings through
various examples of embodiments.
[0033] The terms and words used in the specification and claims
should not be interpreted as being limited to typical meanings or
dictionary definitions, but should be interpreted as having
meanings and concepts relevant to the technical scope of the
embodiments disclosed in the specification.
[0034] In an embodiment, a composition for coating a photoresist
pattern includes: a polymer compound represented by the following
formula 1; and a solvent:
##STR00005##
[0035] wherein each of R* and R** is independently a hydrogen or a
methyl group; R.sub.1 is a linear or branched hydrocarbon group
having 1 to 18 carbon atoms, an ether group containing a linear or
branched hydrocarbon group having 1 to 18 carbon atoms, or a cyclic
hydrocarbon group having 3 to 18 carbon atoms; each of R.sub.2 to
R.sub.4 is independently a linear or branched hydrocarbon group
having 1 to 18 carbon atoms or a cyclic hydrocarbon group having 3
to 18 carbon atoms;
[0036] N.sup.+X.sup.- is an ammonium salt.
[0037] the molar ratio of a:b ranges from 10:90 to 90:10,
preferably from 30:70 to 70:30.
[0038] Specifically, N.sup.+X.sup.- is NH.sup.+Cl.sup.-,
NH.sup.+I.sup.-, NH.sup.+HSO.sub.4.sup.-, (NH.sup.+)COO.sup.-,
(NH.sup.+)SO.sub.3, (NH.sup.+)SO.sub.4.sup.-,
(NH.sup.+)PO.sub.3.sup.-, or (NH.sup.+)PO.sub.4.sup.-.
[0039] The polymer compound represented by formula 1 includes
compounds represented by the following formulas 1a to 1h:
##STR00006## ##STR00007##
[0040] According to the embodiment, the hydroxyl group and ammonium
base contained in the polymer compound can react with an underlying
photoresist material to form a cross-linking material in a
subsequent baking process. That is, the cross-linking material is
obtained by cross-linking between the photoresist material and the
compound represented the formula 1. The photoresist material forms
an underlying photoresist pattern.
[0041] For example, an esterification reaction between the end
hydroxyl group of the polymer compound and the carboxylic acid of
the photoresist material occurs in the presence of an acid
catalyst. The acid catalyst is generated from a photoacid generator
included in the underlying photoresist pattern. The esterification
reaction occurs during the baking process. See reaction scheme 1
below. Due to the cross-linking reaction, a thin layer, which is
also referred to as a coating layer, is formed on the surface of
the underlying photoresist material. When the coating layer is
formed, the size of the photoresist pattern increases and a space
or a distance between two neighboring photoresist patterns
decreases. For example, when a hole is present between two
neighboring photoresist patterns, the size of the hole is reduced
upon formation of the coating layer.
##STR00008##
[0042] Here, (A) denotes the underlying photoresist material and
(B) denotes the compound represented by the formula 1a. Futhermore,
water solubility of the photoresist pattern coating composition
according to the embodiment is increased by the tertiary ammonium
base contained in the polymer compound, and thus defects on the
photoresist pattern surface which may occur when developing and
removing the photoresist pattern coating composition can be
minimized.
[0043] A compound, which is not cross-linked with the
photosensitive polymer during the baking process, can be easily
removed by an alkaline developer in a subsequent removal process.
Herein, the amount of polymer attached to the photoresist pattern
surface can be controlled by controlling the time and temperature
of the baking process.
[0044] According to this embodiment, the photoresist pattern size,
which reached the limit of conventional exposure processes and
photoresist materials, can increase using the photoresist pattern
coating composition of the embodiment, thereby reducing a distance
between two neighboring photoresist patterns. The distance between
two neighboring photoresist patterns defines a hole pattern. Thus,
a hole pattern with a pattern size smaller than a limit allowed in
a given lithography device is formed. As a result, an integration
degree of a device can improve.
[0045] In the photoresist pattern coating composition according to
the embodiment, the content of the polymer compound represented by
formula 1 may be 0.1-3 wt % based on the total weight of the
photoresist pattern coating composition. If the content of the
polymer compound is less than 0.1 wt %, it will be difficult to
form a coating layer on the surface of the photoresist pattern, and
if the content of the polymer compound is more than 3 wt %, the
uniformity of the coating layer will be poor.
[0046] In the photoresist pattern coating composition according to
the embodiment, the solvent may include an alcohol compound. The
photoresist pattern coating composition may further include a
surfactant.
[0047] Herein, the alcohol compound may include a C.sub.1-C.sub.10
alkylalcohol, a C.sub.2-C.sub.10 alkoxy alkylalcohol, or a mixture
thereof. Specifically, the C.sub.1-C.sub.10 alkylalcohol may
include methanol, ethanol, propanol, isopropanol, n-butanol,
sec-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol,
2,2-dimethyl-1-propanol, or a mixture thereof.
[0048] Furthermore, the C.sub.2-C.sub.10 alkoxy alkylalcohol may
include 2-methoxyethanol, 2-(2-methoxyethoxy)ethanol,
1-methoxy-2-propanol, 3-methoxy-1,2-propanoldiol, or a mixture
thereof.
[0049] The surfactant serves to increase the coating property of
the coating composition to thereby provide a uniform coating
surface. The surfactant that is used in the embodiment may be a
conventional surfactant. For example, an anionic surfactant, a
cationic surfactant, or an amphoteric surfactant may be used alone
or in a mixture depending on the size and thickness of the
photoresist pattern. More specific examples of the surfactant
include alkylbenzene sulfonate surfactants, higher amine halides,
quaternary ammonium surfactants, alkyl pyridinium surfactants,
amino acid surfactants, sulfonimide surfactants, and the like.
[0050] The content of the surfactant is preferably 0.001-0.1 wt %
based on the total weight of the photoresist pattern coating
composition.
[0051] In addition, the photoresist pattern coating composition
according to the embodiment may further include additives such as
an acid catalyst, a surfactant, a basic compound and the like in
order to improve resolution and coating properties.
[0052] The acid catalyst serves to increase the crosslinking
density or rate during formation of the coating layer. For example,
the acid catalyst that is used in the embodiment may be
hydrochloric acid, sulfuric acid, phosphoric acid, methylsulfonic
acid, ethylsulfonic acid, propylsulfonic acid, butylsulfonic acid,
benzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid,
p-toluenesulfonic acid (PTSA), camphorsulfonic acid,
naphthylsulfonic acid, cyclohexylsulfonic acid, acetic acid,
ethylacetic acid, propylacetic acid, isopropylacetic acid, or
mixtures thereof.
[0053] The surfactant serves to increase the coating property of
the coating composition to thereby provide a uniform coating
surface. The surfactant that is used in the embodiment may be a
conventional surfactant. For example, an anionic surfactant, a
cationic surfactant or an amphoteric surfactant may be used alone
or in a mixture depending on the size and thickness of the
photoresist pattern. More specific examples of the surfactant
include alkylbenzene sulfonate surfactants, higher amine halides,
quaternary ammonium surfactants, alkyl pyridinium surfactants,
amino acid surfactants, sulfonimide surfactants, and the like.
[0054] In addition, the basic compound that is used in the
embodiment serves as a crosslinker and a stabilizer and may be a
conventional amine compound. For example, the basic compound may be
triethanolamine (TEOA), 2-aminoethanol, 2-(2-aminoethoxy)ethanol,
or the like.
[0055] The content of the additives is preferably 0.001-0.1 wt %
based on the total weight of the pattern coating composition. If
the content of the additives is less than 0.001 wt %, the effect of
the additives will be insufficient. Thus, the quality of the
coating layer becomes poor, or the effect of increasing the rate of
crosslinking in the coating layer cannot be obtained. If the
content of the additives is more than 0.1 wt %, the quality of the
coating layer becomes poor, or an excessive loss of the photoresist
pattern can occur during formation of the coating layer to thereby
deteriorate the surface of the photoresist pattern.
[0056] Furthermore, the photoresist pattern coating composition
according to the embodiment has the following properties, and thus
can effectively reduce the size of a space or hole. The space or
the hole is defined by the photoresist pattern and is obtained by
forming a uniform coating layer on the photoresist pattern: (1) the
photoresist pattern coating composition does not damage a
photoresist material and/or an underlying layer pattern. The
photoresist pattern coating composition can form a uniform coating
layer when it is coated on an underlying photoresist pattern by a
spin-coating technique; (2) the photoresist pattern coating
composition has excellent adhesion properties so as to form a thin
layer on the surface of the photoresist pattern when the coating
composition is applied; (3) the photoresist pattern coating
composition has etching resistance similar to or higher than that
of conventional photoresist materials; (4) the photoresist pattern
coating composition does not form foams on the surface of the
photoresist pattern when it is applied; and (5) the photoresist
pattern coating composition has an almost vertical profile
(80-100.degree.) after it is applied.
[0057] In another embodiment, there is provided a method for
forming a fine pattern, the method including: a) forming a first
photoresist pattern on a semiconductor substrate; b) coating the
photoresist pattern coating composition of the embodiment on the
formed first photoresist pattern; c) baking the photoresist pattern
having the photoresist pattern coating composition coated thereon,
thereby forming a coating layer at the interface between the
photoresist pattern and the photoresist pattern coating
composition; and d) removing an unreacted portion of the
photoresist pattern coating composition, which does not form the
coating layer, thereby forming a second photoresist pattern
including the coating layer formed on the first photoresist
pattern.
[0058] Herein, the baking step is preferably performed at a
temperature of 100 to 200.degree. C., particularly 160.degree. C.
or lower, more particularly 100 to 150.degree. C., for 30 seconds
to 1 minute. That is, the amount of polymer attached to the
photoresist pattern surface can be controlled depending on the
baking temperature. If the baking temperature is lower than
100.degree. C., the effect of coating the composition will be
insufficient, and if the baking temperature is higher than
200.degree. C., the polymer will be excessively attached to plug a
space between two neighboring photoresist patterns.
[0059] Hereinafter, embodiments will be described in detail with
reference to the accompanying drawings. FIGS. 1 to 3 are schematic
process views illustrating a method for forming a fine pattern
using the pattern coating composition according to the
embodiment.
[0060] Referring to FIG. 1, a layer 123 and a photoresist layer
(not shown) are sequentially formed on a semiconductor substrate
121. The photoresist layer (not shown) is subjected to exposure and
development processes, thereby forming a first photoresist pattern
125.
[0061] Herein, the material that is used to form the photoresist
layer is not specifically limited. A conventional positive
photoresist material or negative photoresist material may be
employed. Specifically, a positive photoresist material is
preferably used to form the photoresist layer.
[0062] The exposure process is preferably performed with exposure
energy of 0.1-100 mJ/cm.sup.2 using KrF (248 nm), ArF (193 nm), VUV
(157 nm), EUV (13 nm), E-beams, X-rays or ion beams as a light
source.
[0063] In addition, the method may further include performing a
soft baking process before the exposure process and performing a
post baking process after the exposure process. The baking process
is preferably performed at a temperature ranging from 70.degree. C.
to 200.degree. C. The development process is performed using an
alkaline developer such as an aqueous solution containing 0.01-5 wt
% of tetramethylammonium hydroxide (TMAH). The line width (CD) of
the first photoresist pattern obtained by the development process
is preferably 30-300 nm, particularly 50 to 250 nm.
[0064] Next, referring to FIG. 2, the photoresist pattern coating
composition as described above may be coated on the first
photoresist pattern 125 by a spin-coating technique, thereby
forming a photoresist pattern coating composition layer 126.
Herein, the photoresist pattern coating composition can be prepared
by adding the compound of formula 1 and optionally additives to a
solvent and filtering the mixture through a 0.2-.mu.m filter.
[0065] Next, referring to FIG. 3, the photoresist pattern having
the photoresist pattern coating composition coated thereon is
baked, thereby forming a coating layer 127 at the interface between
the photoresist pattern and the photoresist pattern coating
composition.
[0066] During the baking process, the thickness, size or the like
of the coating layer can further be controlled by suitably
controlling the baking temperature and time. Herein, the baking
step is preferably performed at a temperature of 160.degree. C. or
lower, particularly 100.degree. C. to 250.degree. C., for 30
seconds to 1 minute.
[0067] Next, an unreacted portion of the photoresist pattern
coating composition, which was not cross-liked with the
photosensitive polymer on the photoresist pattern surface, may be
removed using a developer.
[0068] In addition, the removal of the photoresist pattern coating
composition may be performed using water, a basic or alkaline
developer.
[0069] As a result, according to the disclosed embodiment, a space
or a distance between two neighboring photoresist patterns can be
effectively reduced using the photoresist pattern coating
composition of the embodiment, for example, a pattern shrink
material, thus increasing the integration density of circuits.
[0070] According to the method of the embodiment, the second
photoresist pattern having a line width (CD) that is about 10-40%
greater than the line width (CD) of the first photoresist pattern
can be formed. For example, when the ratio of a line width (CD) to
a space width of the first photoresist pattern is 1:1, the ratio of
a line width (CD) to a space width of the second photoresist
pattern is preferably 1:0.6-09. In addition, the thickness of the
coating layer is preferably 30-3000 .ANG., particularly 1500 .ANG..
The coating layer has a third width, and wherein the third width is
5-20% of the first width.
[0071] In still another embodiment, a device includes a substrate
and a photoresist pattern formed on the substrate. The photoresist
pattern is formed by the fine pattern forming method of the
disclosed embodiment. The photoresist pattern has a coating layer.
The coating layer contains the ammonium base-containing polymer
compound as described above.
[0072] Hereinafter, examples will be described in detail. However,
these examples are merely for illustrative purposes and are not
intended to be restrictive.
EXAMPLES
[0073] I. Preparation of Photoresist Pattern Coating Polymer
Preparation Example 1
[0074] 13.0 g (0.1 mol) of a monomer of the following formula 2,
19.4 g (0.1 mol) of a monomer of the following formula 3, and 0.7 g
of azobis(isobutyronitrile) (AIBN) were placed in a reactor. The
reaction materials were dissolved in 100 g of acetonitrile, and
then polymerized at 70.degree. C. for 24 hours. After completion of
the polymerization reaction, the reaction product was slowly added
dropwise to an excessive amount of diethyl ether and was
precipitated therein, after which it was dissolved in acetonitrile.
The dissolved product was precipitated again in diethyl ether,
thereby preparing a polymer represented by formula 1a. The
weight-average molecular weight (Mw) and polydispersity (PD) of the
synthesized polymer were measured using GPC (gel permeation
chromatography) (GPC analysis: Mw=3,600, and PD=1.95).
##STR00009##
Preparation Example 2
[0075] A polymer represented by formula 1c was prepared in the same
manner as described in Preparation Example 1, except that 25.5 g
(0.1 mol) of a monomer of the following formula 4 was used instead
of the monomer of formula 3. The weight-average molecular weight
(Mw) and polydispersity (PD) of the synthesized polymer were
measured using GPC (gel permeation chromatography) (GPC analysis:
Mw=4,800, and PD=2.01).
##STR00010##
Preparation Example 3
[0076] A polymer represented by formula 1e was prepared in the same
manner as described in Preparation Example 1, except that 11.6 g
(0.1 mol) of a monomer of the following formula 5 was used instead
of the monomer of formula 2. The weight-average molecular weight
(Mw) and polydispersity (PD) of the synthesized polymer were
measured using GPC (gel permeation chromatography) (GPC analysis:
Mw=5,100, and PD=2.11).
##STR00011##
Preparation Example 4
[0077] A polymer represented by formula 1f was prepared in the same
manner as described in Preparation Example 2, except that 38.6 g
(0.1 mol) of a monomer of the following formula 6 was used instead
of the monomer of formula 2. The weight-average molecular weight
(Mw) and polydispersity (PD) of the synthesized polymer were
measured using GPC (gel permeation chromatography) (GPC analysis:
Mw=3,700, and PD=1.99).
##STR00012##
[0078] II. Preparation of Photoresist Pattern Coating
Composition
Examples 1-1 to 1-4
[0079] As shown in Table 1 below, 2.7 g of the photoresist pattern
coating polymers synthesized in Preparation Examples 1 to 4, and
0.3 g of a water-soluble surfactant (a sulfonamide-based
surfactant, TCI) were completely dissolved in 17.0 g of deionized
water or 17.0 g of a 6:4 mixture of deionized water and
isopropanol, and the solution was filtered through a 0.2-.mu.m disc
filter, thereby preparing photoresist pattern coating
compositions.
TABLE-US-00001 TABLE 1 Amount Deionized Polymer used Surfactant
water Alcohol Example 1-1 Polymer 1a 2.7 g 0.3 g 17.0 g Example 1-2
Polymer 1c 2.7 g 0.3 g 17.0 g Example 1-3 Polymer 1e 2.7 g 0.3 g
17.0 g Example 1-4 Polymer 1f 2.7 g 0.3 g 10.2 g 6.8 g
[0080] III. Method for Formation of Fine Pattern for Semiconductor
Device
[0081] Step 1
[0082] 2 g of an ArF photoresist polymer (molecular weight (Mw):
10,100; polydispersity (PD): 1.89; x: y: z (mole %)=45: 40: 15)
represented by the following formula 7, 0.02 g of
triphenylsulfonium triflate and 0.01 g of triethanolamine were
dissolved in 10 g of propylene glycol monomethyl ether acetate
(PGMEA) to form a solution. The solution was filtered through a
0.2-.mu.m filter, thereby preparing a photoresist composition. A
wafer with a first contact hole pattern is prepared. The first
contact hole pattern has a size of 100 nm. See FIG. 4.
##STR00013##
[0083] Step 2
[0084] Thereafter, on each of wafers having the first photoresist
pattern, each of the photoresist pattern coating compositions
prepared in Examples 1-1 to 1-4 was spin-coated to form a thin
layer, followed by soft baking in an oven or on a hot plate at
150.degree. C. for 60 seconds. Then, each of the wafers was dipped
in deionized water or an aqueous solution containing 2.38 wt % of
tetramethylammonium hydroxide (TMAH) for 60 seconds to develop the
first photoresist contact hole pattern, thereby forming a second
photoresist contact hole pattern. See FIG. 5. The change in size
(critical dimension (CD)) of the second photoresist pattern is
shown in Table 2 below.
TABLE-US-00002 TABLE 2 CD of first PR CD of second PR
Classification pattern pattern First photoresist -- 100 nm --
pattern -- Example 1-1 -- 83 nm -- Example 1-2 -- 87 nm -- Example
1-3 -- 86 nm -- Example 1-4 -- 81 nm
[0085] IV. Measurement of a Thickness of Coating Layer Depending on
Various Baking Temperatures
[0086] Step 1
[0087] 2 g of an ArF photoresist polymer (molecular weight (Mw):
10,100; polydispersity (PD): 1.89; a: b: c (mole %)=45: 40: 15)
represented by the above formula 7, 0.02 g of triphenylsulfonium
triflate and 0.01 g of triethanolamine were dissolved in 10 g of
propylene glycol monomethyl ether acetate (PGMEA), and the solution
was filtered through a 0.2-.mu.m filter, thereby preparing a
photoresist composition. A first contact hole pattern having a size
of 100 nm was prepared.
[0088] Step 2
[0089] Thereafter, on the wafer having the first photoresist
pattern formed thereon, the photoresist pattern coating composition
prepared in Examples 1-1 was spin-coated to form a thin layer,
followed by soft baking at various temperatures as shown in Table 3
below. Then, each of the wafers was dipped in deionized water or an
aqueous solution containing 2.38 wt % of tetramethylammonium
hydroxide (TMAH) for 60 seconds to develop the first photoresist
contact hole pattern, thereby forming a second photoresist pattern.
The change in the contact hole pattern size (CD) of the second
photoresist pattern depending on a change in the baking temperature
is shown in Table 3 below.
TABLE-US-00003 TABLE 3 CD of first PR contact hole CD of second PR
Thickness of the pattern pattern coating layer 120.degree. C. 100
nm 97 nm 3 130.degree. C. 90 nm 10 140.degree. C. 86 nm 14
150.degree. C. 83 nm 17 160.degree. C. 76 nm 24 170.degree. C. 67
nm 33
[0090] According to the embodiments as described above, a fine
photoresist pattern can be formed in a simple manner by coating the
formed photoresist pattern with a photoresist pattern coating
composition according to an embodiment. Since an unreacted material
can be easily removed from the coating layer during development
after formation of the coating layer, no additional development
process is required. Thus, the disclosed embodiment is
cost-effective. This method of the embodiment can be advantageously
used in any semiconductor processes to overcome a wavelength
limit.
[0091] While various embodiments have been described above, it will
be understood to those skilled in the art that the embodiments
described are by way of example only. Accordingly, the composition
and method described herein should not be limited based on the
described embodiments.
* * * * *